[TYPO3] sys_workflow new page version bug?

[Pascal Cramer]

Hi all,

in my search for a comprehensible workflow system I came across the 
sys_workflows extension which is just perfect for the workflow setup my customer 
is looking for: authorized, user/group configurable and quite easy to use.

Unfortunately, there is one 'thing' which I cannot seem to fix/resolve.
When working with a new version of a page, the preview of that new version 
results in the error message:
--------------------------
Error!

The requested page didn't have a proper connection to the tree-root!

(Broken rootline)
--------------------------

I have added some info to an existing bug report:
http://bugs.typo3.org/view.php?id=1893

Could anybody tell this a bug in the extension or a misconfiguration somewhere 
in the system? I am using sys_workflows 2.5.1 and 4.0.4.
As you can see, I have added a reward for the correct fix of this issue.
Hope someone can help so we can get this site 'on the road' :-)

Thanks,
Pascal
.. and of course: all the best for the new year